人為什么會起雞皮疙瘩?
冷風(fēng)疹子、小疙瘩、雞皮疙瘩--有好幾個(gè)別名來形容這種情況。人的皮膚上有時(shí)候會起一些小疹子，看起來就像雞拔掉羽毛后的樣子。
And the cold， a sad tune or powerful scene from a movie can trigger this phenomenon when you least expect it。
人在遇到寒冷的時(shí)候，聽到悲傷的曲調(diào)的時(shí)候，或者從電影中看到令人震撼的場景的時(shí)候，就會產(chǎn)生這種你最不愿看到的現(xiàn)象。
In this week’s episode of BrainCraft， Youtuber Vanessa Hill dives into the weird and wonderful science of why humans experience the chilling sensation of goosebumps。
在本周的“大腦飛船”節(jié)目里，凡妮莎·希爾在油土鱉上展示了這一怪異而又奇妙的科學(xué)，解釋了為什么人會起雞皮疙瘩的疑問。
The scientific term for this evolutionary trait is pilomotor reflex or piloerection。
科學(xué)上描述這一進(jìn)化特征的專有名詞是“豎毛反射”或者“立毛”。
‘I want you to think of the last time you remember experiencing them，’ says Hill in the YouTube clip。
希爾在油土鱉視頻上說道：“我希望你們想一想最后一次起雞皮疙瘩的情形。”
‘Was it at the beginning of this video?’
“那是不是在視頻開始的時(shí)候。”
‘And if not， was it from the cold? Or music? A movie? Were you just having an intense emotional response to something?’
“如果不是，那么因?yàn)橛隼?音樂?或者電影?或者說你當(dāng)時(shí)對什么東西有強(qiáng)烈的情緒反應(yīng)?”
She continues to explain when hair standing to attention， it forms a buffer between your skin and the cold air –helping you to thermorgulate or regulate your body temperature。
希爾繼續(xù)解釋說道，當(dāng)毛發(fā)豎起來的時(shí)候，在皮膚和冷空氣之間形成了一道屏障--從而幫助你調(diào)節(jié)溫度或者說控制體溫。
This is why most people tend to get goosebumps when they are cold or feel a chill。
那也正是為什么人在冷或者感覺冷的時(shí)候會起雞皮疙瘩。
The sensation is caused by the tiny muscles underneath each follicle， called arrector pili， and when they contract， the hair is pulled upright。
這種感覺是由每個(gè)毛囊里的細(xì)小肌肉造成的，被稱之為“立毛肌”，當(dāng)這些肌肉收縮時(shí)，毛發(fā)就會立起來。
‘These are involuntary muscles and they’re part of our sympathetic nervous system， which is responsible for most fight or flight responses，’ explains Hill。
希爾解釋說道：“這些是‘不隨意肌’，是我們交感神經(jīng)系統(tǒng)的一部分，這個(gè)系統(tǒng)產(chǎn)生了大多數(shù)的應(yīng)激反應(yīng)。”
‘The reaction is closely tied to our emotional state， and apart from being cold， this is why movies may be the best trigger for goosebumps。’
“這個(gè)反應(yīng)的產(chǎn)生和我們的情緒狀態(tài)有著密切的關(guān)系，這也正是為什么除了感覺冷以外，人們最經(jīng)常因?yàn)殡娪岸痣u皮疙瘩。”
However， listening to music has also triggered the reaction in a majority of adults。
但是，聽音樂也會讓大多數(shù)成年人起雞皮疙瘩。
Experts believe that this is ‘just the structure and nature of music itself’， as it creates anticipation in the brain。
專家們認(rèn)為這是“因?yàn)橐魳繁旧淼慕Y(jié)構(gòu)和內(nèi)容的緣故”，因?yàn)橐魳吩谌四X中產(chǎn)生了預(yù)期。
Although it seems you are deeply involved in the music of a song， your brain is actually working hard to predict the next lyric or note and the internal stakes builds within us subconsciously。
盡管你看起來沉醉在了一首歌的音樂里，但是實(shí)際上你的大腦正在努力運(yùn)轉(zhuǎn)來預(yù)測下一句歌詞或內(nèi)容，在無意識的情況下都能夠產(chǎn)生內(nèi)部風(fēng)險(xiǎn)。
Another theory suggest that sad songs are more likely to give us the chills， compared to happy ones。
據(jù)另一項(xiàng)理論指出，和歡快的歌曲相比，悲傷的曲調(diào)更容易讓人起雞皮疙瘩。
This is because sad or nostalgic music has the ability to create chilling feelings of social loss。
這是因?yàn)楸瘋蛘邞雅f的音樂能夠讓人對社會上的挫折產(chǎn)生寒冷的感覺。
‘Feeling separate from your family or social group is known to give rise to goosebumps， but the reason why isn’t well understood，’ says Hill。
希爾說道：“和家庭或者社會組織脫離的感覺會讓人起雞皮疙瘩，但是個(gè)中緣由卻還不是很清楚。”
‘We do know that getting shivers down the spine from music activates the same brain structures as other things that make us feel euphoric – like food and some drugs。’
“我們的確知道音樂可以讓人顫抖激動不已，因?yàn)橐魳房梢韵衿渌屛覀冇鋹偟臇|西(例如食物和某些藥品)一樣，激活我們的大腦中的同一結(jié)構(gòu)。
This is because brain imaging studies have found that goosebumps activates structures like the amygdala and parts of the prefrontal cortex -- both found associated with pleasure and reward。
關(guān)于大腦成像的研究已經(jīng)發(fā)現(xiàn)，雞皮疙瘩能夠激活人類大腦中的杏仁核神經(jīng)元和部分額葉皮質(zhì)--這兩部分都和大腦的愉悅和激勵(lì)有關(guān)。
And there is no rhyme or reason to when this sensation will occur， as it is sometimes brought on by a distant memory of a past event。
而且雞皮疙瘩的產(chǎn)生沒有任何規(guī)律或者理由可尋，因?yàn)橛袝r(shí)人們會因?yàn)橛洃浿芯眠h(yuǎn)以前的一件事而起雞皮疙瘩。
However， this phenomenon is one which descends from our ancient ancestors who used it to keep warm and it may have even kept them alive by deterring predators -- but experts have deemed this reaction useless to modern day humans。
但是，這一現(xiàn)象是從我們的先祖那里繼承而來的，他們曾利用這一反應(yīng)來保持體溫。并且嚇跑捕食者--但是專家們認(rèn)為對于現(xiàn)代人類來說，這種反應(yīng)毫無作用。
However， goosebumps are very important to some creatures of the world， such as cats， dogs and other mammals who use it has a way to seem larger and scarier to their predators。
但是雞皮疙瘩對地球上其他一些生物來說卻非常重要，例如貓、狗和其他哺乳動物，它們用這一現(xiàn)象來使得自己看起來更大一些，從而嚇跑捕食者。
